1. Field of the Invention
The present invention relates to a rehabilitating pipe laid inside an existing pipe, such as a sewer pipe, for the purpose of rehabilitating the existing pipe, and a method of laying such a rehabilitating pipe.
2. Description of the Prior Art
A method of rehabilitating an existing pipe is known from Japanese Patent Application Publication No. 2003-214098, wherein a compound pipe is constructed to rehabilitate an existing pipe like a sewer pipe by, as shown in FIG. 16, assembling and laying inside an existing pipe 4 a rehabilitating pipe 3 whose outer diameter is slightly less than the inner diameter of the existing pipe 4, and then filling and hardening a filler (not shown) in the gap between the outer periphery of the rehabilitating pipe 3 and the inside wall surface of the existing pipe 4. The rehabilitating pipe 3 comprises segments 1 for the rehabilitating pipe. Namely, as shown in FIG. 17, a rehabilitating pipe 3 is assembled inside a manhole 5 in communication with the existing pipe 4 by an assembly worker S assembling a short, ring-shaped pipe unit 2 by coupling the arcuate segments 1 in the circumferential direction of the arcs thereof (the circumferential direction of the rehabilitating pipe 3), wherein bolts 9 for coupling in the longitudinal direction have previously been affixed, and then mutually coupling pipe units 2 inside the existing pipe 4 in the longitudinal direction of the pipe units 2 (the longitudinal direction of the rehabilitating pipe 3) by bolts 9 and nuts (not shown).
In the invention structure, the overall length of each bolt 9 is slightly less than two times the width of each segment 1 in the longitudinal direction; the bolt 9 is inserted through a bolt through hole (not shown), from one side of the segment 1 along the longitudinal direction; and the segments 1 are fixed by nuts so that the tip parts of the bolts 9 protrude from the other side of the segments 1 for a length slightly less than the width of the segment 1 in the longitudinal direction. Furthermore, the pipe units 2 are mutually coupled by passing the bolts 9 that protrude from the segments 1 of one pipe unit 2 through the bolt through holes of the segments 1 of another pipe unit 2, pushing the aforementioned another pipe unit 2 into the aforementioned one pipe unit 2, and tightening the passed through bolts 9 with nuts.
Nevertheless, there is a problem of considerable danger in the structure of coupling the segments 1 of the pipe units 2 in the longitudinal direction in the conventional rehabilitating pipe 3, i.e., because the bolts 9 fixed to each of the segments 1 assembled in the pipe units 2 protrude from one side of the segments 1 for a length (e.g., slightly less than 20 cm) slightly less than the width thereof in the longitudinal direction, there is a risk that the protruding parts of the bolts 9 may strike an assembly worker's face and the like particularly when the assembly worker rolls, carries, and couples the pipe units 2 inside the dark existing pipe 4.
In addition, there is a problem in the conventional structure in that the work of coupling is laborious and time consuming because it is necessary to screw and tighten the nuts in order to fasten the bolts 9 to the segments 1 beforehand, and further to screw and tighten the nuts to the bolts 9 also when coupling the pipe units 2 in the longitudinal direction.
In addition, the bolts 9 are buried in the filler and serve a role the same as the rebars in steel reinforced concrete when filling and hardening the filler in the gap between the outer periphery of the rehabilitating pipe 3 and the inside wall surface of the existing pipe 4 after laying the rehabilitating pipe 3; however, there is a problem in that, when calculating the strength of the compound pipe comprising the rehabilitating pipe 3 and the filler, the strength cannot be evaluated because the bolts 9 are not mutually coupled as one unit.
It is therefore an object of the present invention to solve the aforementioned problems, by providing a rehabilitating pipe wherein the work of assembling the rehabilitating pipe, particularly the work of coupling the segments in the longitudinal direction, can be performed safely, simply, and in a short time period, and wherein the strength of the coupling members in the longitudinal direction can be evaluated when calculating the strength of the compound pipe; and also to provide a method of laying such a rehabilitating pie.